JEE Main 2020 (Online) 2nd September Evening Slot
Paper was held on Wed, Sep 2, 2020 9:30 AM
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Chemistry

1
The oxidation states of transition metal atoms in K2Cr2O7, KMnO4 and K2FeO4, respectively, are x, y and z. The sum of x, y and z is _______.
2
Two compounds A and B with same molecular formula (C3H6O) undergo Grignard’s reaction with methylmagnesium bromide to give products C and D. Products C and D show following chemical tests. JEE Main 2020 (Online) 2nd September Evening Slot Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 208 English
C and D respectively are :
3
The shape / structure of [XeF5] and XeO3F2, respectively, are
4
Simplified absorption spectra of three complexes ((i), (ii) and (iii)) of Mn+ ion are provided below; their $$\lambda $$max values are marked as A, B and C respectively. The correct match between the complexes and their $$\lambda $$max values is JEE Main 2020 (Online) 2nd September Evening Slot Chemistry - Coordination Compounds Question 261 English
(i) [M(NCS)6](–6 + n)
(ii) [MF6](–6 + n)
(iii) [M(NH3)6]n+
5
The number of subshells associated with n = 4 and m = –2 quantum numbers is
6
The heat of combustion of ethanol into carbon dioxide and water is – 327 kcal at constant pressure. The heat evolved (in cal) at constant volume and 27oC (if all gases behave ideally) is (R = 2 cal mol–1 K–1) ________.
7
For the disproportionation reaction
2Cu+(aq) ⇌ Cu(s) + Cu2+(aq) at 298 K. ln K
(where K is the equilibrium constant) is
___________ × 10–1.
Given :
($$E_{C{u^{2 + }}/C{u^ + }}^0 = 0.16V$$
$$E_{C{u^ + }/Cu}^0 = 0.52V$$
$${{RT} \over F} = 0.025$$)
8
The work function of sodium metal is 4.41 $$ \times $$ 10–19 J. If photons of wavelength 300 nm are incident on the metal, the kinetic energy of the ejected electrons will be (h = 6.63 $$ \times $$ 10–34 J s; c = 3 $$ \times $$ 108 m/s) ________ × 10–21 J.
9
The size of a raw mango shrinks to a much smaller size when kept in a concentrated salt solution. Which one of the following processes can explain this?
10
The one that is not expected to show isomerism is :
11
The correct observation in the following reactions is : JEE Main 2020 (Online) 2nd September Evening Slot Chemistry - Biomolecules Question 146 English
12
The ratio of the mass percentages of ‘C & H’ and ‘C & O’ of a saturated acyclic organic compound ‘X’ are 4 : 1 and 3 : 4 respectively. Then, the moles of oxygen gas required for complete combustion of two moles of organic compound ‘X’ is ________.
13
Match the type of interaction in column A with the distance dependence of their interaction energy in column B
A B
(i) ion-ion (a) $${1 \over r}$$
(ii) dipole-dipole (b) $${1 \over {{r^2}}}$$
(iii) London dispersion (c) $${1 \over {{r^3}}}$$
(d) $${1 \over {{r^6}}}$$
14
The results given in the below table were obtained during kinetic studies of the following reaction

2A + B $$ \to $$ C + D JEE Main 2020 (Online) 2nd September Evening Slot Chemistry - Chemical Kinetics and Nuclear Chemistry Question 155 English
X and Y in the given table are respectively :
15
If you spill a chemical toilet cleaning liquid on your hand, your first aid would be
16
Three elements X, Y and Z are in the 3rd period of the periodic table. The oxides of X, Y and Z, respectively, are basic, amphoteric and acidic. The correct order of the atomic numbers of X, Y and Z is :
17
The molecular geometry of SF6 is octahedral. What is the geometry of SF4 (including lone pair(s) of electrons, if any)?
18
The major product of the following reaction is : JEE Main 2020 (Online) 2nd September Evening Slot Chemistry - Alcohols, Phenols and Ethers Question 132 English
19
An organic compound ‘A’ (C9H10O) when treated with conc. HI undergoes cleavage to yield compounds ‘B’ and ‘C’. ‘B’ gives yellow precipitate with AgNO3 where as ‘C’ tautomerizes to ‘D’. ‘D’ gives positive iodoform test. ‘A’ could be
20
Arrange the following labelled hydrogens in decreasing order of acidity : JEE Main 2020 (Online) 2nd September Evening Slot Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 209 English
21
Consider the reaction sequence given below: JEE Main 2020 (Online) 2nd September Evening Slot Chemistry - Haloalkanes and Haloarenes Question 134 English
Which of the following statements is true?
22
The major product obtained from E2 - elimination of 3-bromo-2-fluoropentane is

Mathematics

1
If the equation cos4 $$\theta $$ + sin4 $$\theta $$ + $$\lambda $$ = 0 has real solutions for $$\theta $$, then $$\lambda $$ lies in the interval :
2
Let A = {X = (x, y, z)T: PX = 0 and

x2 + y2 + z2 = 1} where

$$P = \left[ {\matrix{ 1 & 2 & 1 \cr { - 2} & 3 & { - 4} \cr 1 & 9 & { - 1} \cr } } \right]$$,

then the set A :
3
If y = $$\sum\limits_{k = 1}^6 {k{{\cos }^{ - 1}}\left\{ {{3 \over 5}\cos kx - {4 \over 5}\sin kx} \right\}} $$,

then $${{dy} \over {dx}}$$ at x = 0 is _______.
4
For some $$\theta \in \left( {0,{\pi \over 2}} \right)$$, if the eccentricity of the
hyperbola, x2–y2sec2$$\theta $$ = 10 is $$\sqrt 5 $$ times the
eccentricity of the ellipse, x2sec2$$\theta $$ + y2 = 5, then the length of the latus rectum of the ellipse, is :
5
If the sum of first 11 terms of an A.P.,
a1, a2, a3, .... is 0 (a $$ \ne $$ 0), then the sum of the A.P.,
a1 , a3 , a5 ,....., a23 is ka1 , where k is equal to :
6
If the variance of the terms in an increasing A.P.,
b1 , b2 , b3 ,....,b11 is 90, then the common difference of this A.P. is_______.
7
Let f : (–1, $$\infty $$) $$ \to $$ R be defined by f(0) = 1 and
f(x) = $${1 \over x}{\log _e}\left( {1 + x} \right)$$, x $$ \ne $$ 0. Then the function f :
8
If a curve y = f(x), passing through the point (1, 2), is the solution of the differential equation,
2x2dy= (2xy + y2)dx, then $$f\left( {{1 \over 2}} \right)$$ is equal to :
9
Let the position vectors of points 'A' and 'B' be
$$\widehat i + \widehat j + \widehat k$$ and $$2\widehat i + \widehat j + 3\widehat k$$, respectively. A point 'P' divides the line segment AB internally in the ratio $$\lambda $$ : 1 ( $$\lambda $$ > 0). If O is the origin and
$$\overrightarrow {OB} .\overrightarrow {OP} - 3{\left| {\overrightarrow {OA} \times \overrightarrow {OP} } \right|^2} = 6$$, then $$\lambda $$ is equal to______.
10
Let [t] denote the greatest integer less than or equal to t.
Then the value of $$\int\limits_1^2 {\left| {2x - \left[ {3x} \right]} \right|dx} $$ is ______.
11
Consider a region R = {(x, y) $$ \in $$ R : x2 $$ \le $$ y $$ \le $$ 2x}. if a line y = $$\alpha $$ divides the area of region R into two equal parts, then which of the following is true?
12
The imaginary part of
$${\left( {3 + 2\sqrt { - 54} } \right)^{{1 \over 2}}} - {\left( {3 - 2\sqrt { - 54} } \right)^{{1 \over 2}}}$$ can be :
13
Let f : R $$ \to $$ R be a function which satisfies
f(x + y) = f(x) + f(y) $$\forall $$ x, y $$ \in $$ R. If f(1) = 2 and
g(n) = $$\sum\limits_{k = 1}^{\left( {n - 1} \right)} {f\left( k \right)} $$, n $$ \in $$ N then the value of n, for which g(n) = 20, is :
14
Let EC denote the complement of an event E. Let E1 , E2 and E3 be any pairwise independent events with P(E1) > 0

and P(E1 $$ \cap $$ E2 $$ \cap $$ E3) = 0.

Then P($$E_2^C \cap E_3^C/{E_1}$$) is equal to :
15
Let f(x) be a quadratic polynomial such that
f(–1) + f(2) = 0. If one of the roots of f(x) = 0
is 3, then its other root lies in :
16
$$\mathop {\lim }\limits_{x \to 0} {\left( {\tan \left( {{\pi \over 4} + x} \right)} \right)^{{1 \over x}}}$$ is equal to :
17
Let n > 2 be an integer. Suppose that there are n Metro stations in a city located along a circular path. Each pair of stations is connected by a straight track only. Further, each pair of nearest stations is connected by blue line, whereas all remaining pairs of stations are connected by red line. If the number of red lines is 99 times the number of blue lines, then the value of n is :
18
Let a, b, c $$ \in $$ R be all non-zero and satisfy
a3 + b3 + c3 = 2. If the matrix

A = $$\left( {\matrix{ a & b & c \cr b & c & a \cr c & a & b \cr } } \right)$$

satisfies ATA = I, then a value of abc can be :
19
The set of all possible values of $$\theta $$ in the interval
(0, $$\pi $$) for which the points (1, 2) and (sin $$\theta $$, cos $$\theta $$) lie
on the same side of the line x + y = 1 is :
20
The area (in sq. units) of an equilateral triangle inscribed in the parabola y2 = 8x, with one of its vertices on the vertex of this parabola, is :

Physics

1
A square shaped hole of side l = $${a \over 2}$$ is carved out at a distance d = $${a \over 2}$$ from the centre ‘O’ of a uniform circular disk of radius a. If the distance of the centre of mass of the remaining portion form O is $$ - {a \over X}$$ , value of X (to the nearest integer) is : JEE Main 2020 (Online) 2nd September Evening Slot Physics - Center of Mass and Collision Question 82 English
2
In a Young’s double slit experiment, 16 fringes are observed in a certain segment of the screen when light of a wavelength 700 nm is used. If the wavelength of light is changed to 400 nm, the number of fringes observed in the same segment of the screen would be
3
A particle of mass m is moving along the x-axis with initial velocity $$u\widehat i$$. It collides elastically with a particle of mass 10 m at rest and then moves with half its initial kinetic energy (see figure). If $$\sin {\theta _1} = \sqrt n \sin {\theta _2}$$ then value of n is ________. JEE Main 2020 (Online) 2nd September Evening Slot Physics - Center of Mass and Collision Question 81 English
4
A wire of density 9 $$ \times $$ 10–3 kg cm–3 is stretched between two clamps 1 m apart. The resulting strain in the wire is 4.9 $$ \times $$ 10–4. The lowest frequency of the transverse vibrations in the wire is : (Young’s modulus of wire Y = 9 $$ \times $$ 1010 Nm–2), (to the nearest integer), _________
5
A 10 $$\mu $$F capacitor is fully charged to a potential difference of 50 V. After removing the source voltage it is connected to an uncharged capacitor in parallel. Now the potential difference across them becomes 20 V. The capacitance of the second capacitor is :
6
If momentum (P), area (A) and time (T) are taken to be the fundamental quantities then the dimensional formula for energy is
7
The height ‘h’ at which the weight of a body will be the same as that at the same depth ‘h’ from the surface of the earth is (Radius of the earth is R and effect of the rotation of the earth is neglected)
8
When the temperature of a metal wire is increased from 0oC to 10oC, its length increases by 0.02%. The percentage change in its mass density will be closest to :
9
A wire carrying current I is bent in the shape ABCDEFA as shown, where rectangle ABCDA and ADEFA are perpendicular to each other. If the sides of the rectangles are of lengths a and b, then the magnitude and direction of magnetic moment of the loop ABCDEFA is JEE Main 2020 (Online) 2nd September Evening Slot Physics - Magnetic Effect of Current Question 163 English
10
Two uniform circular discs are rotating independently in the same direction around their common axis passing through their centres. The moment of inertia and angular velocity of the first disc are 0.1 kg-m2 and 10 rad s–1 respectively while those for the second one are 0.2 kg-m2 and 5 rad s–1 respectively. At some instant they get stuck together and start rotating as a single system about their common axis with some angular speed. The kinetic energy of the combined system is :
11
An ideal gas in a closed container is slowly heated. As its temperature increases, which of the following statements are true?
(A) the mean free path of the molecules decreases.
(B) the mean collision time between the molecules decreases.
(C) the mean free path remains unchanged.
(D) the mean collision time remains unchanged.
12
A capillary tube made of glass of radius 0.15 mm is dipped vertically in a beaker filled with methylene iodide (surface tension = 0.05 Nm–1, density = 667 kg m–3) which rises to height h in the tube. It is observed that the two tangents drawn from liquid-glass interfaces (from opp. sides of the capillary) make an angle of 60o with one another. Then h is close to (g = 10 ms–2)
13
An ideal cell of emf 10 V is connected in circuit shown in figure. Each resistance is 2 $$\Omega $$. The potential difference (in V) across the capacitor when it is fully charged is ______. JEE Main 2020 (Online) 2nd September Evening Slot Physics - Capacitor Question 118 English
14
A charge Q is distributed over two concentric conducting thin spherical shells radii r and R (R > r). If the surface charge densities on the two shells are equal, the electric potential at the common centre is : JEE Main 2020 (Online) 2nd September Evening Slot Physics - Electrostatics Question 197 English
15
An inductance coil has a reactance of 100 $$\Omega $$. When an AC signal of frequency 1000 Hz is applied to the coil, the applied voltage leads the current by 45o. The self-inductance of the coil is
16
The figure shows a region of length ‘l’ with a uniform magnetic field of 0.3 T in it and a proton entering the region with velocity 4 $$ \times $$ 105 ms–1 making an angle 60o with the field. If the proton completes 10 revolution by the time it cross the region shown, ‘l’ is close to
(mass of proton = 1.67 $$ \times $$ 10–27 kg, charge of the proton = 1.6 $$ \times $$ 10–19 C) JEE Main 2020 (Online) 2nd September Evening Slot Physics - Magnetic Effect of Current Question 164 English
17
The displacement time graph of a particle executing S.H.M is given in figure :
(sketch is schematic and not to scale) JEE Main 2020 (Online) 2nd September Evening Slot Physics - Simple Harmonic Motion Question 121 English
Which of the following statements is/are true for this motion?
(A) The force is zero at t = $${{3T} \over 4}$$
(B) The acceleration is maximum at t = T
(C) The speed is maximum at t = $${{T} \over 4}$$
(D) The P.E. is equal to K.E. of the oscillation at t = $${{T} \over 2}$$
18
In the following digital circuit, what will be the output at ‘Z’, when the
input (A, B) are (1, 0), (0, 0), (1, 1,), (0, 1) JEE Main 2020 (Online) 2nd September Evening Slot Physics - Semiconductor Question 168 English
19
In a hydrogen atom the electron makes a transition from (n + 1)th level to the nth level. If n >> 1, the frequency of radiation emitted is proportional to :
20
In a plane electromagnetic wave, the directions of electric field and magnetic field are represented by $$\widehat k$$ and $$2\widehat i - 2\widehat j$$, respectively. What is the unit vector along direction of propagation of the wave?
21
A light ray enters a solid glass sphere of refractive index $$\mu $$ = $$\sqrt 3 $$ at an angle of incidence 60o. The ray is both reflected and refracted at the farther surface of the sphere. The angle (in degrees) between the reflected and refracted rays at this surface is ________.
22
A particle is moving 5 times as fast as an electron. The ratio of the de-Broglie wavelength of the particle to that of the electron is 1.878 $$ \times $$ 10–4. The mass of the particle is close to
23
A small point mass carrying some positive charge on it, is released from the edge of a table. There is a uniform electric field in this region in the horizontal direction. Which of the following options then correctly describe the trajectory of the mass?
(Curves are drawn schematically and are not to scale). JEE Main 2020 (Online) 2nd September Evening Slot Physics - Electrostatics Question 198 English